Validation of the Infectious Disease Society of America/American Thoracic Society 2007 guidelines for severe community-acquired pneumonia.

OBJECTIVES: Validate the Infectious Disease Society of America/American Thoracic Society 2007 (IDSA/ATS 2007) criteria for predicting severe community-acquired pneumonia (SCAP) and evaluate a health-services definition for SCAP.

DESIGN: Retrospective cohort study.

SETTING: LDS Hospital, an academic tertiary care facility in the western United States.

PATIENTS: Consecutive patients with International Classification of Diseases, Ninth Edition, codes and chest radiographs consistent with community-acquired pneumonia from 1996 to 2006 seen at LDS Hospital.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: We utilized the electronic medical record to examine intensive care unit admission, intensive therapies received, and predictors of severity, as well as 30-day mortality. We also developed logistic regression models of mortality and disease severity. We calculated the IDSA/ATS 2007 criteria as well as three other pneumonia severity scores. We defined SCAP as receipt of intensive therapy in the intensive care unit. In 2413 episodes of pneumonia, 1540 were admitted to the hospital, while 379 were admitted to the intensive care unit. Overall 30-day mortality was 3.7% but was 16% among intensive care patients. The IDSA/ATS 2007 minor criteria predicted SCAP with an area under the curve of 0.88 (95% confidence interval 0.85-0.90), which improved to 0.90 (95% confidence interval 0.88-0.92) with weighting. Competing models had area under the curve of 0.76 to 0.83. Using four rather than three minor criteria improved the positive predictive value from 54% to 81%, with a stable negative predictive value of 94% to 92%.

CONCLUSIONS: The IDSA/ATS 2007 criteria predicted pneumonia severity better than other models. Using four rather than three minor criteria may be a superior cutoff, although this will depend on institutional characteristics.